Incumbent governments have been very hard to defeat recently. Is that about to change?

Since 2011, one federal government and seven provincial governments have won re-election, on several occasions against all expectations. Only one incumbent since 2011 has been defeated: Jean Charest's Quebec Liberals, who fell short of the Parti Québécois by less than one percentage point and only four seats in 2012.

But by this time next year, that strong record for incumbent governments may be in tatters.

The first domino to fall might be Darrell Dexter's NDP government in Nova Scotia. The province is widely expected to be in an election campaign in a matter of weeks. But the New Democrats have not led in any opinion poll in over a year, and the last set of numbers put the party almost 20 points behind Stephen McNeil's Liberals.

The minority governments in Ontario and Quebec should also be put to the test soon, and both could meet defeat by the spring. Though Tim Hudak's Progressive Conservatives seem to be in internal turmoil, the Ontario Liberals have yet to extricate themselves from the mess Dalton McGuinty left related to the cancelling of two gas plant projects. Kathleen Wynne is also being challenged on the other side of the political spectrum by Andrea Horwath’s NDP. By 2014, it will be a challenge for the premier to win re-election and extend her party's reign after 11 years in power.

The Liberals under Philippe Couillard are in a much better position in Quebec, leading the governing PQ by more than 10 points in the latest polls. Satisfaction with Pauline Marois' government, elected only last September, is now as low as it was when Charest was sent packing.

But these three incumbents have more in common than just their precarious holds on power. When the next elections are called in their provinces, they will all face the electorate as incumbents for the first time: Dexter and Marois because they are only in their first terms, and Wynne because she took over from McGuinty mid-mandate.

However, there is good reason not to rule them out just yet. Of those eight successful incumbent governments since 2011, half of them went on the hustings with rookie leaders: Greg Selinger in Manitoba, Kathy Dunderdale in Newfoundland and Labrador, Alison Redford in Alberta, and Christy Clark in British Columbia. Selinger and McGuinty were both far from assured of victory when their campaigns for re-election began, while Redford and Clark trailed their opponents by double-digits before emerging victorious.

Dexter, Marois, and Wynne would also be justified in believing their chances are not so bad. Wynne's Liberals are still competitive in the polls, while Hudak's personal numbers remain abysmal. And public opinion has not been gauged in Nova Scotia and Quebec for several months — support may have shifted since then, with Dexter's government already in pre-campaign mode and Marois generally seen as having handled the Lac-Mégantic tragedy well.

Simply due to incumbents' recent 8-1 record, it is hard to bet against these three leaders. But with their poll numbers not pointing to re-election, it seems unlikely that all of these underdogs will defy expectations.

Éric Grenier taps The Pulse of federal and regional politics for Huffington Post Canada readers every week. Grenier is the author of ThreeHundredEight.com, covering Canadian politics, polls and electoral projections.